The invention is in the field of circular tubular (annular) fluorescent light units, such as screw-in units for use in lamps having shades, eg. floor lamps and table lamps.
Various ways have been devised for mounting circular fluorescent lights in floor lamps and table lamps. For example, U.S. Pat. No. 3,742,208 to Mills discloses a screw-in circular fluorescent light unit which includes a ballast or transformer in the unit, and the following U.S. patents disclose non-screw-in circular fluorescent lamps in shade-type lamps: U.S. Pat. Nos. 2,350,462 to Johns; 2,450,302 to Rowe; 2,507,074 to Wiedenhoeft; 2,534,955 to Dazley; and 3,148,836 to Potye.
In the above-referenced patents, the circular lamps lie in a horizontal plane, and are surrounded by a lamp shade. Many such lamp shades are translucent, so as to shade direct glare of the light source, and at the same time to transmit or radiate a certain amount of the light for a pleasing appearance and to somewhat illuminate the surroundings. Due to the circular configuration of the light source, it can cause bands of unequal brightness to occur on the shade. These unequal brightness bands are considered by many people to be unsightly, weird, and/or distracting.